Someone recently told me that it is impossible to buy fresh yams in the US, and that all yams on display in supermarkets are actually just sweet potatoes. While yams may not be grown in the US, I’m pretty sure that the ones I see in my local grocery store are different than sweet potatoes (they look different anyway) and regardless of where they are grown I can still buy fresh yams if I want to.
So who’s right? Are those things labeled yams really just sweet potatoes in disguise and it’s impossible to buy real freash “yams” in the US?
What are called yams in most US supermarkets, are, indeed a variety of sweet potato. True yams come from Africa and aren’t very common. Cecil had an article on this:
If you live in a large city with a substantial immigrant population, then true yams are not hard to find. (Or, more accurately, chunks of yam, sealed with wax on the cut end; they’re too big to sell whole.) But you’re going to be looking at a “Fruitteria” or “[Ethnicity] Market,” not at your chain megamart. If what you’re looking at is under a pound per rhizome, it’s almost certainly not a yam, but a variety of sweet potato.
Also, even using superstore nomenclature, yams and sweet potatoes are two different types of potato.
Just as “regular” potatoes come in waxy (good for roasting) and starchy (good for mashing, whole baked potatoes) varieties*, so too do sweet potatoes come in waxy and starchy versions (not from the same breed of plant, obviously). One version is called a yam, and one is referred to simply as a sweet potato. I can’t remember which is which at the moment.
“regular” potatoes actually have a third variety that falls between starchy and waxy, but I didn’t mention it since I don’t think sweet potatoes have a middle version and I didn’t want to confuse folks with asymmetric analogies.
True yams are huge, starchy, white and bland. They are used as a staple carbohydrate in various tropical cuisines. You wouldn’t expect to find yams in a US supermarket, but they can sometimes be found in some ethnic food markets.
In the US, the word “yam” can also refer to a type of sweet potato. This is what you are likely seeing in the supermarket.
It originally didn’t have the “what.” Popeye (and his catch phrase) came from the Thimble Theater comic strip by E.C. Segar. When the Fleischer Brothers started making Popeye cartoons in 1933, they added the “what” to make it fit the meter of his theme song.
The “yams” that I know of, that I see in the stores, are also called “garnet” or “red garnet” yams. They are reddish-purple on the outside, bright orange/yellow inside, much more irregular in shape, and don’t closely resemble the things I know of as “sweet potatoes” (which more closely resemble Russet potatoes except a little more yellow/orangey).
Am I to understand from this thread that these two tubers are actually just different cultivars of the same species, most generically called the “sweet potato”?
Yes. Both Ipomoea batatas, a member of the morning glory family. And they seem a lot more similar to me than the various cultivars of Brassica oleracea, for instance.
In my area of California, the Ipomea batatas cultivars are numerous, at least in natural foods type markets. They have pale, yellow, or orange flesh and somewhat different shapes and sizes and skin colors. Much like apple varieties. Whether you call them yams (confusing them with the unrelated African carbohydrate crop) or sweet potatoes (confusing them with the unrelated potato), they all taste rather similar. Supposedly, the darker orange the flesh, the more vitamins they have.
